Homes in Colorado tend to have high radon levels because much of our soil consists of broken down granite from the mountains, and granite tends to contain a significant amount of uranium (see Are my granite countertops safe?, below). Note that in the EPA map of radon zones that most of the rocky mountain region tends to be high, and almost all of Colorado is high. Radon is found in all homes, but the amount varies greatly. The amount of radon in a given home is unpredictable, and all homes should be tested.
A huge body of scientific evidence indicates that radon is the second leading cause of lung cancer. Radon was first documented as causing lung cancer in mine workers. Extensive studies in mines helped to establish the risk levels associated with various levels of radon. These tables can be found on the EPA website at epa.gov/radon. One of the most famous case studies of radon in homes took place in Grand Junction Colorado, where many homes were built on uranium tailings and many people died of lung cancer because of it. Radon breaks down into several other radioactive elements called “daughters”, which can enter the lungs when we breathe. Polonium 218 and 214 are particularly dangerous “daughters” because they are electrically charged so they will stick in our lungs or will stick to dust particles that then stick in our lungs. They break down to the next level in the radioactive decay process and release alpha radiation that damages our delicate lung tissue and causes lung cancer.
There are many approved methods to measure radon. Long term testing is the most accurate, but it is not practical for a real estate transaction. Both radon canisters and continuous radon monitors are approved methods to measure radon for a 48 hour minimum short term test for real estate transactions. We use a continuous radon monitor because it helps prevent tampering, and we can report the results immediately at the end of the 48 hour test. Both methods require “closed house conditions” for 12 hours prior to the test and during the 48 hour test. Closed house conditions require windows and doors to be closed except for normal entry and exit, and that no large volume fans such as attic fans or swamp coolers are operated. Violation of the closed house conditions can be detected by a continuous radon monitor, since it records the radon level hourly. The radon level is measured in PCL which means Picocuries per liter, the standard of measurement for radiation. When the radon is at or above 4.0 PCL, radon should be mitigated.
Yes! Radon can be mitigated in most homes for about $750 to $1000.00. An approved contractor will evaluate the home and install the necessary mitigation. Normally, they will bore a large hole in the basement slab. A plastic pipe is sealed into the hole and connects to a fan that removes the radon and blows it to the exterior. If the dwelling has a crawl space, a perforated pipe installed on the soil, and a sealed barrier is installed over the pipe and soil and the fan connects to the perforated pipe and blows it to the exterior.
Yes! According to the EPA, granite countertops do not pose a significant risk, even though they may contain a significant amount of uranium. Radiation emitted by the countertops poses little risk because unlike your lungs, your skin is an effective barrier against the radiation it might emit. It is only a contributing factor in that it can add to the level of radon in your home if it has a significant amount of uranium in it. Radon testing of countertops is not necessary, just do an EPA approved test and mitigate the radon if it tests at 4.0 PCL or above.